Escherichia coli (hereinafter referred to as ‘E. coli’) is a Gram-negative, short rod-shaped bacterium belonging to the genus Escherichia and the family Enterobacteriaceae, and is one of the normal flora existing in the intestines of various animals including mammals. It was known that most of the strains of E. coli are non-pathogenic and may cause opportunistic infections, but some highly pathogenic strains cause diverse intestinal diseases and sepsis in animals including humans.
An example of E. coli may include enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enterohemorrhagic E. coli (EHEC), enteroaggregative E. coli (EAEC), enteroinvacive E. coli (EIEC), necrotoxigenic E. coli (NTEC), or the like. It is known that among them, particularly, ETEC generates infectious disease associated with E. coli in swine.
Currently, as a large number of swine are collectively bred in a pork industry, colibacillosis in swine has been in the spotlight as a most frequent and troublesome disease (Non-Patent Document 1). Recently, occurrence of swine colibacillosis has increased in Korea, which has caused growth retardation and death of young swine due to diarrhea, resulting in tremendous economic losses to farmers (Non-Patent Document 2).
In order to prevent and treat colibacillosis in swine, many antibiotics have been administered to swine in the prior art, but when antibiotics has been misused or overused, the misused or overused antibiotics may give rise to drug resistance and remain in bodies of the swine. Therefore, currently, the use of antibiotics has been restricted around the world (Non-Patent Document 3).
Meanwhile, bacteriophage is a specialized type of virus that infects and destroys only bacteria, and can self-replicate only inside host bacteria. The bacteriophage has strong host specificity as compared to antibiotics, and recently, a problem of emergence of strain resistant against antibiotics has been serious, such that an interest in practical use of the bacteriophage has increased (Non-Patent Documents 4 and 5).
Therefore, research into the bacteriophage has been actively conducted in various countries around the world, and in addition to a patent application for bacteriophage, an attempt to acquire Food and Drug Administration (FDA) approval for a composition containing the bacteriophage has been gradually increased.
As the prior art for the bacteriophage, 7 kinds of bacteriophages for controlling E. coli 0157:H have been disclosed in Patent Document 1, and a bacteriophage having a specific bactericidal activity against Staphylococcus aureus has been disclosed in Patent Document 2. Further, lytic protein derived from a bacteriophage specifically destroying a peptidoglycan structure of bacterial cell membrane, and bacteria lysates by the lytic protein have been disclosed in Patent Document 3.
However, in spite of presence of the following prior arts, a technology associated with the bacteriophage for preventing and/or treating infectious diseases by ETEC that are a still important problem in an livestock industry including the pork industry is still insufficient, such that a bacteriophage and a technology associated with the bacteriophage should be developed.